Emulsion with coke additive in hydrocarbon phase and process for preparing same

ABSTRACT

A process for preparing a hydrocarbon in water emulsion includes the steps of providing a hydrocarbon phase containing inactive natural surfactant; mixing a solid carbon additive with the hydrocarbon phase, the solid additive being selected from the group consisting of coal, coke and mixtures thereof so as to provide a hydrocarbon suspension including the solid carbon additive; and forming an emulsion from the hydrocarbon suspension and an aqueous phase in the presence of a surfactant activating additive so as to activate the inactive natural surfactant and form a hydrocarbon in water emulsion having the solid carbon additive suspended in the hydrocarbon phase. A hydrocarbon in water emulsion is also provided including a hydrocarbon phase, a water phase, a surfactant, and a solid carbon additive suspended in the hydrocarbon phase, the solid carbon additive being selected from the group consisting of coal, coke and mixtures thereof.

BACKGROUND OF THE INVENTION

[0001] The invention relates to a hydrocarbon in water emulsion andprocess for preparing same and, more particularly, to an emulsion andprocess including a solid carbon additive, especially coal or coke,which is useful in enhancing the energy potential of the emulsion as afuel, and which also allows the emulsion to be used in pavingprocedures, while maintaining stability of the emulsion duringtransportation and storage.

[0002] Refineries on a worldwide basis produce large amounts of coke,the disposal of which can pose problems. This coke typically is presentas a solid, further complicating the proper disposal of same.

[0003] The need exists for a technique or method which utilizes coke soas provide an advantageous disposition of same.

[0004] Bitumen emulsions are typically used as a source of combustiblefuel. One problem frequently encountered with such fuel is that thesulfur content of the bitumen poses problems.

[0005] The need also remains for a bitumen emulsion wherein a reducedsulfur content is provided per unit of energy produced.

[0006] It is therefore the primary object of the present invention toprovide a method for incorporating coke into an emulsion for use as acombustible fuel and/or in paving procedures.

[0007] It is a further object of the present invention to provide amethod for incorporating solid carbon additives such as coal or cokeinto a bitumen in water emulsion so as to provide a material useful as acombustible fuel having a reduced sulfur content per unit of energyproduced or as a paving material.

[0008] Other objects and advantages of the present invention will appearhereinbelow.

SUMMARY OF THE INVENTION

[0009] In accordance with the present invention, the foregoing objectsand advantages are readily attained.

[0010] According to the invention, a process for preparing a hydrocarbonin water emulsion is provided, which process comprises the steps of:providing a hydrocarbon phase; mixing a solid carbon additive with saidhydrocarbon phase, said solid carbon additive being selected from thegroup consisting of coal, coke and mixtures thereof so as to provide ahydrocarbon suspension including said solid additive; and forming anemulsion from said hydrocarbon suspension and an aqueous phase in thepresence of a surfactant so as to form a hydrocarbon in water emulsionhaving said solid additive suspended in said hydrocarbon phase.

[0011] In further accordance with the present invention, a hydrocarbonin water emulsion is provided which is extremely useful as a combustiblefuel or as a paving material, which emulsion comprises a hydrocarbonphase, a water phase, a surfactant, and a solid carbon additivesuspended in the hydrocarbon phase, said solid carbon additive beingselected from the group consisting of coal, coke and mixtures thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The invention relates to a hydrocarbon in water emulsion andprocess for preparing same, and particularly to a viscous hydrocarbon orbitumen in water emulsion, wherein the bitumen is provided with a solidcarbon additive suspended therein which renders the emulsion useful as apaving material and also as a combustible fuel, and which further servesto provide an emulsion having excellent stability at a reasonable cost.

[0013] The hydrocarbon phase of the emulsion and process of the presentinvention may suitably be any hydrocarbon, especially viscoushydrocarbon, from which it is desirable to form emulsions in water so asto enhance the transportability thereof. Emulsions of viscoushydrocarbon in water are useful as a combustible fuel and, according tothe invention, as paving materials for use in paving roads and the like.

[0014] Most naturally occurring viscous hydrocarbon material containsinactive surfactants including carboxylic acids, phenols and esterswhich, under proper conditions, can be activated as surfactants.

[0015] These inactive natural surfactants can be activated andstabilized using additives. The use of amine additives to activate theinactive natural surfactants is disclosed in U.S. Pat. No. 5,480,583 toRivas et al.

[0016] The incorporation of additional components into emulsions canvery frequently have a destabilizing or other adverse effect on theresulting emulsion. In accordance with the present invention, however,it has been found that by using amine additives to activate the naturalsurfactants contained in the heavy hydrocarbon phase, a stable emulsionincluding the solid carbon additive incorporated into the hydrocarbonphase can be provided.

[0017] According to the invention, the solid carbon additive to be usedmay suitably be a particulate coke additive, which provides an emulsionwhich is well suited for use in paving operations, or a particulate coaladditive which can be used to maintain the energy levels produced bycombustion of the emulsion, while potentially reducing the overallsulfur content of the emulsion as desired through the use of lowersulfur coal, which is particularly advantageous in light of desired orrequired emission levels of combustion processes.

[0018] The solid carbon additive, either coal or coke, may typically beobtained having a solid structure of widely diverse particle size. Inaccordance with the present invention, this solid is preferably treated,for example using milling and the like, to reduce the particle size ofthe solid carbon additive, preferably to a size less than or equal toabout 30 microns. This may be carried out, for example, using avibratory cryogenic mill such as the 6700 Freezer Mill of SPEXIndustries. Of course, if the starting material is obtained alreadyhaving the desired particle size, no additional milling is needed.

[0019] The hydrocarbon phase is preferably a viscous hydrocarbon havingan API gravity of less than or equal to about 16, preferably less thanor equal to about 8.1, and a viscosity at 120° F. of greater than orequal to about 100 cp. A specific example of a suitable hydrocarbon foruse in accordance with the present invention is Cerro Negro bitumen,which may typically have the following composition. TYPICAL CERRO NEGROBITUMEN Gravity API 60° C. 8.1 Saturates % (wt.) 29.4 Aromatics % 35.6Resins % 18.9 Asphaltenes % 16.1 Acidity (mg KOH/g) 3.02 Carbon % 80.3Hydrogen % 9.9 Nitrogen (ppm) 6188 Sulfur % 3.7 Vanadium (ppm) 367.4Nickel (ppm) 95.5 Sodium (ppm) 11.8 Conradson Carbon % 17.2 Water % 0.1

[0020] The water or aqueous phase of the emulsion may suitably be waterfrom any convenient source, and preferably includes the amine additivefor activating the natural surfactant of the bitumen. Suitable amineadditives include combinations of amines and sodium hydroxide (NaOH) asdescribed in U.S. Pat. No. 5,480,583.

[0021] The aqueous phase of the emulsion is preferably providedcontaining the amine additive in an amount corresponding to betweenabout 800 ppm and about 2500 ppm wt. with respect to the bitumen.

[0022] In accordance with the present invention, it has also been foundthat the mixing of a solid carbon additive with the hydrocarbon phase,wherein the solid additive is mixed in a specific ratio to thehydrocarbon phase, and is present at desired particle sizes ordiameters, serves to enhance the stability of the emulsion while alsoenhancing the combustion and/or paving characteristics of the emulsion.Solid carbon additives in accordance with the present invention arepreferably oil insoluble, and may include coal, coke resulting frombituminous coal or petroleum processes and the like, and mixturesthereof.

[0023] In accordance with the present invention, the solid carbonadditive is preferably provided having an average particle size lessthan or equal to about the mean droplet size of the hydrocarbon phase inthe final emulsion such that the solid particles remain suspended withinhydrocarbon droplets as desired. In this regard, the solid carbonadditive of the present invention is preferably provided having anaverage particle size less than a mean volume diameter (D(₄,₃)) of thehydrocarbon, wherein the mean volume diameter is defined as follows:

D _((4,3))=(Σdi ⁴ /vi)/(Σdi ³ /vi),

[0024] wherein di is the mean diameter of band “i” of a histogram of theemulsion, and vi is the accumulated volume of droplets in thatparticular band. The solid additive in accordance with the presentinvention is preferably provided having an average particle size of lessthan or equal to about 30 microns, most preferably less than or equal toabout 15 microns.

[0025] The solid additive is preferably also mixed with hydrocarbon inaccordance with the present invention in amounts which are less than orequal to about 10% wt. of the hydrocarbon, or 800 ppm based on totalemulsion, so as to further reduce the possibility for sedimentation ofthe solid additive. In this regard, it has been found that solidadditive may suitably be mixed with the hydrocarbon according to thefollowing relation

Φ_(S)/(Φ_(H)+Φ_(S))≦K,

[0026] wherein Φ_(S) is the volume fraction of the solid additive, Φ_(H)is the volume fraction of the hydrocarbon, and K is 0.1.

[0027] In order to insure the internal dispersion of solid additivethrough the hydrocarbon or bitumen phase, the bitumen may preferably beheated to a temperature sufficient to allow substantially homogeneousmixture. For example, Cerro Negro bitumen may suitably be heated to atemperature of at least about 60° C. or higher prior to mixing with thesolid additive.

[0028] The emulsion of the present invention may preferably be preparedas follows. Initially, the viscous hydrocarbon phase is provided. Thedesired solid additive in accordance with the present invention is alsoprovided, and may need to be milled or otherwise treated so as toprovide a suitable average particle size.

[0029] The solid particles are then mixed with the hydrocarbon phase,preferably heated as discussed above, so as to allow the internaldispersion of the solid within the hydrocarbon. This suspension of solidparticles in hydrocarbon is then used to form a hydrocarbon in wateremulsion by mixing with an aqueous phase as discussed above, andsubjecting the mixture to sufficient mixing energy so as to provide anoil-in-water emulsion preferably having an average droplet size of thehydrocarbon phase of between about 1 μm and about 30 μm, and having aratio by volume of hydrocarbon/water of between about 85/15 and about70/30. Most preferably, in accordance with the present invention, theemulsion may be formed by mixing the hydrocarbon/solid suspension with aportion of the aqueous phase so as to provide an 85/15 emulsion, andsubsequently diluting the emulsion to a desired 70/30 ratio.

[0030] The solid carbon particles, either coke or coal, are preferablydispersed in the bitumen in a blending process which may be carried outfor a time preferably between about 1 and about 10 minutes, morepreferably between about 2 and about 4 minutes and at a temperature ofbetween about 50° C. and about 90° C., more preferably between about 65°C. and about 75° C. The solid carbon particles and bitumen arepreferably blended at a ratio by weight of bitumen to particles ofbetween about 1:1 and 25:1.

[0031] Once the solid carbon additive has been provided having thedesired particle size, and in the proper amounts based upon the bitumen,the final emulsion is formed using bitumen with suspended solid and awater phase which may preferably be provided with the additive, forexample containing about 2000 mg/l of monoethanolamine and, preferably,having a sodium concentration equivalent to about 20 mg/l of Na+ ions inthe final emulsion. As set forth above, the monoethanolamine and NaOHserve to activate natural surfactant present in the bitumen and toprovide a final emulsion product having suitable stability.

[0032] During the mixing stage, the bitumen is preferably maintained ata temperature of about 60° C., and the water with amine/NaOH additive ismixed in a mixer preferably during a pre-mixing stage at 200 rpm forabout 2 minutes, followed by mixing at 1500 rpm for an additional 2minutes so as to provide a stable emulsion. At this stage, the bitumenwith solid and water are preferably mixed so as to provide an emulsionhaving a ratio by volume of bitumen to water of between about 80/20 andabout 90/10, preferably about 85/15. This intermediate emulsion is thendiluted using additional water, preferably to a final emulsion having abitumen/water ratio of about 70/30. The dilution may suitably be carriedout while mixing for a period of about 1 minute, preferably at about1000 rpm.

[0033] This invention may be embodied in other forms or carried out inother ways without departing from the spirit or essentialcharacteristics thereof. The present embodiment is therefore to beconsidered as in all respects illustrative and not restrictive, thescope of the invention being indicated by the appended claims, and allchanges which come within the meaning and range of equivalency areintended to be embraced therein.

What is claimed is:
 1. A process for preparing a hydrocarbon in wateremulsion, comprising the steps of: providing a hydrocarbon phasecontaining inactive natural surfactant; mixing a solid carbon additivewith said hydrocarbon phase, said solid additive being selected from thegroup consisting of coal, coke and mixtures thereof so as to provide ahydrocarbon suspension including said solid carbon additive; and formingan emulsion from said hydrocarbon suspension and an aqueous phaseincluding a surfactant activating additive so as to activate saidinactive natural surfactant and form a hydrocarbon in water emulsionhaving said solid carbon additive suspended in said hydrocarbon phase.2. A process according to claim 1 , wherein said hydrocarbon is aviscous hydrocarbon having an API gravity of less than or equal to about16, and a viscosity at 122° F. of greater than or equal to about 100 cp.3. A process according to claim 1 , wherein said hydrocarbon is CerroNegro bitumen.
 4. A process according to claim 1 , wherein said solidcarbon additive is coke.
 5. A process according to claim 1 , whereinsaid solid carbon additive is coal.
 6. A process according to claim 1 ,further comprising providing said solid carbon additive having anaverage particle size of less than or equal to about a mean droplet sizeof said hydrocarbon phase in said emulsion.
 7. A process according toclaim 1 , further comprising providing said solid carbon additive havingan average particle size which is less than a mean volume diameterD_((4,3)) of said hydrocarbon, which is defined as follows: D_((4,3))=(Σdi ⁴ /vi)/(Σdi ³ /vi), wherein di is mean diameter of band iof a histogram of said emulsion, and vi is accumulated volume ofdroplets in said band.
 8. A process according to claim 1 , furthercomprising providing said solid carbon additive having an averageparticle size of less than or equal to about 30 μm.
 9. A processaccording to claim 1 , further comprising providing said solid carbonadditive having an average particle size of less than or equal to about15 μm.
 10. A process according to claim 1 , further comprising mixingsaid solid carbon additive with said hydrocarbon in an amount less thanor equal to about 10% wt. of said hydrocarbon.
 11. A process accordingto claim 1 , further comprising mixing said solid additive with saidhydrocarbon according to the following: Φ_(S)/(Φ_(H)+Φ_(S))≦K, whereinΦ_(S) is volume fraction of said solid additive, Φ_(H) is volumefraction of said hydrocarbon, and K is 0.1.
 12. A process according toclaim 1 , wherein said forming step comprises mixing said hydrocarbonsuspension with said aqueous phase so as to provide an initial emulsionhaving a ratio by volume of hydrocarbon/water of about 85/15, anddiluting said initial emulsion with additional water to provide a finalemulsion having a ratio by volume of hydrocarbon/water of about 70/30.13. A process according to claim 1 , wherein said surfactant activatingadditive comprises an amine and NaOH in amounts effective to activatesaid natural surfactant and stabilize the emulsion.
 14. A hydrocarbon inwater emulsion comprising a hydrocarbon phase, a water phase, asurfactant, and a solid carbon additive suspended in the hydrocarbonphase, said solid carbon additive being selected from the groupconsisting of coal, coke and mixtures thereof.
 15. An emulsion accordingto claim 14 , wherein said hydrocarbon phase is a viscous hydrocarbonhaving an API gravity of less than or equal to about 16, and a viscosityat 122° F. of greater than or equal to about 100 cp.
 16. An emulsionaccording to claim 14 , wherein said hydrocarbon is Cerro Negro bitumen.17. An emulsion according to claim 14 , wherein said solid carbonadditive is coke.
 18. An emulsion according to claim 14 , wherein saidsolid carbon additive is coal.
 19. An emulsion according to claim 14 ,wherein said solid carbon additive has an average particle size of lessthan or equal to about a mean droplet size of said hydrocarbon phase insaid emulsion.
 20. An emulsion according to claim 14 , wherein saidsolid carbon additive has an average particle size which is less than amean volume diameter D_((4,3)) of said hydrocarbon, which is defined asfollows: D _((4,3))=(Σdi ⁴ /vi)/(Σdi ³ /vi), wherein di is mean diameterof band i of a histogram of said emulsion, and vi is accumulated volumeof droplets in said band.
 21. An emulsion according to claim 14 ,wherein said solid carbon additive has an average particle size of lessthan or equal to about 30 μm.
 22. An emulsion according to claim 14 ,wherein said solid carbon additive has an average particle size of lessthan or equal to about 15 μm.
 23. An emulsion according to claim 14 ,wherein said solid carbon additive is present in said emulsion in anamount less than or equal to about 10% wt. of said hydrocarbon.
 24. Anemulsion according to claim 14 , wherein said solid carbon additive ispresent in said emulsion according to the following:Φ_(S)/(Φ_(H)+Φ_(S))≦K, wherein Φ_(S) is volume fraction of said solidcarbon additive, Φ_(H) is volume fraction of said hydrocarbon, and K is0.1.
 25. An emulsion according to claim 14 , wherein said hydrocarbonphase and said water phase are present at a ratio by volume ofhydrocarbon/water between about 70/30 and about 85/15.
 26. An emulsionaccording to claim 14 , wherein said hydrocarbon phase has an averagedroplet diameter of between about 1 μm and about 30 μm.
 27. An emulsionaccording to claim 14 , wherein said surfactant comprises a naturalsurfactant and an additive for activating the natural surfactant.
 28. Anemulsion according to claim 27 , wherein said additive comprises anamine and sodium hydroxide in amount s effective for activating saidnatural surfactant to stabilize the emulsion.
 29. An emulsion accordingto claim 28 , wherein said emulsion contains said amine in an amountbetween about 800 ppm and about 2500 ppm based on weight of saidhydrocarbon phase.